Flotation of minerals



UNITED STATES PATENT OFFICE.

CLEMENT L. PERKINS AND RALPH E. SAYRE, OF PITTSBURGH, IENNSYLVANIA,

'ASSIGNORS TO METALS RECOVERY COMPANY, OF NEW YORK, N. Y., A CORPO- RATION OF MAINE.

No Drawing.

To all whom it may concern Be it known that we, CLEMENT L. PERKINS and RALPH E. SAYRE, citizens of the United States, residing at Pittsburgh, in the county of'Allegheny, State of Pennsylvania, have invented certain new and useful Improvements in Flotation of Minerals; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the concentration of minerals, such as sulfid ores and the like, by flotation; and is based upon the discovery that improved results can be obtained by carrying out the flotation operation with the addition to the ore or mineral pulp of a thio-urea compound or substance, 6. 9., aromatic thio-urea compounds, such as thiocarbanilid or diphenyl-thiourea. Thiodarbanilid is a non-oleaginous solid material which can nevertheless be distributed throughout the mineral pulp with such uniformity that minimum amounts are required for promoting the concentration of the minerals by flotation.

In using'thiocarbanilid, it may be incorporated with the ore or mineral pulp in any suitable manner, for example, by introducing it into the tube mill in which the ore is being ground, or by digesting it in hot water and mixing the product with the ore pulp just before it enters the fiotation cell, or by dissolving the thiocarbanilid in an organic solvent therefor, or in one of the usual flotation oils or oil mixtures, and incorporating the resulting solution with the ore pulp, or in any other suitable manner which will insure the uniform dissemmation of the thiocarbanilid throughout the pulp.

Thiocarbanilid has been found to have a marked action as a eollecting agent and can be used to particula advantage in con unction with other flotation agents which have good frothing qualities. For example, where certain flotation agents, such as terpineol, which have but little selective actlon but good frothing qualities, areemployed, the thiocarbanilid will supplement the action of such agents by its marked selective collecting properties. So also, the thiocarbanilid can be used to advantage to improve the flotation results obtained with flotation Specification of Letters Patent.

Patented Jan. 4, 1921.

Application filed March 25, 1919. Serial No. 284,981.

agents, such as pine oil, for example, which with some ores may have both frothing and selective qualities. Thus pine oil, which cannot by itself be satisfactorily used with certain ores, such as low grade porphyry ores, can be used with excellent results when thiocarbanilid is also used.

After the flotation agent or agents have been thoroughly and uniformly distributed throughout the ore pulp, the resulting mixture is subjected to a flotation operation, as in an ordinary Callow cell, or in apparatus where the air is incorporated in the ore pulp by mechanical agitation.

The action of the thiocarbanilid is sufficicntly marked so that but a small amount thereof will usually be required, for example, as little as one-tenth or one-twentieth of a pound per ton of ore, although improved results have been obtained with as little as 0.02 pounds per ton of ore and with amounts of as much as 1 pound or more per ton of ore. When used in conjunction with other flotation agents, for example, with terpineol or pine oil, a small fraction of a pound of each agent per ton of ore will usually suffice.

lVe have also found that the action of thiocarbanilid can be improved, with certain ores, for example, withcopper sulfid ores (of the Utah Copper Company) by the addition of alkali, for example, of sodium hydroxid or lime, which may be incorporated with the ore and flotation agent in any suitable manner, as by grinding therewith in the usual mill; and we recommend that an alkali be employed with such ores in an amount, for example, of two pounds of caustic soda per ton of ore. With other ores, for example, zinc ore, good results have been obtained where the ore pulp has been of a neutral character and where no added alkali was employed.

The following more detailed description will further illustrate the invention:

A copper sulfid ore (of the Utah Copper Company) was ground in the usual mill with 02 pounds of thiocarbanilid, and 2. pounds of caustic soda per ton of ore. There was also incorporated with the ore pulp a small amount ofterpineol, about one-twentieth of a pound per ton of ore. The result:

ing mixture was .then subjected to a flotation operation in. a Callow cell with the resulting recovery of about 90% of the copper in the form of a concentrate of fiabout 15.3%

from an-ore containing about 1.26% of copper.

Results of a .similar character were obtained with 0.10 pounds of thiocarbanilid per ton of ore and even with as little as 0.05 pounds or even 0.02 pounds per ton of ore;

as Well as amounts of as. much as l or- 2 pounds per ton of ore. 1

It is a characteristic of the process of the present invention, when thiocarbanilid is employedthat the froth obtained is readily broken up; while the concentrate obtalned is cleaner and the recovery usually more complete than when oil, for example, is em-.

ployed as the flotation agent. The concentrates 'first obtained, .for .example, those above referred to, resulting from a single flotation operation in, a rougher cell, can, of course, be further concentrated, and their grade raised by a further 'treatment in a cleaner cell or cells.

The amounts of the flotation agents required according to the present invention, are so small that the process can be used to advantage where there is no return water circuit. men the return water from the tailings and concentrates is used over again, there is recovered an appreciable amount of the reagent which is available for use in the further carrying out of the process When thiocarbanilid is used .in solution, the solvent may be one which is'itself a flotation agent and which will contribute to the carrying outof the flotation operation. The solvent may, however, be itself of a character such that itdoes not promote the flotation, but solvents should not be used which will have a prejudicial efl'ect thereon. The thiocarbanilid may thus, for example, be employed' in solution in; or in admixture with various organic liquids, such as alcohol, or

aromatic amins, such as anilin, xylidin, quinolin, etc.

In place of thiocarbanilid, certain other thioamidor thio-urea substances or compounds, and particularly other aromatic.

I thio-ureas, such as ortho-ditolyl-thiourea, 1 para-ditolyl-thiourea, dixylyl-thiourea prepared from mixed xylidins, monophenylthiourea, etc., can similarly be employed, with resulting advantage to the flotation operation. i

In'our companion application Serial No.

- 337,322 we havev described and claimed the method of eflI'ecting the concentration of mmerals by flotation which there is added to the mineral pulp a small amountiof an organic nitrogen-sulfur compound, said application,. and the more comprehensive claims present application.

thereof, being generic to the invention of the The more specific claims of said companion application are directed to the process in which thio-amido compounds are employed, whereas the claims of the present application are directed tdthe process in which thio-urea compounds are employed. That is, the invention claimed specifically in said companion application is diflerent from that claimed specifically in the present application; while the broader and more comprehensive claims, generic to both specific inventions, are presented in said companion application.

We claim: I

1. The method of efiecting the concentration of mineralsaby flotation, which comprises adding to the mineral vvpulp a small amount of a thio-urea substance or compound, and subjecting the resulting mixture to a flotation operation; substantially as de-- scribed.

2. The method of efl'ecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of an aromatic thio-urea compound, and subjecting the resulting mixture to a flotation operation; substantially as described. a

*3. The method of effecting the concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of thiocarbanilld, and subjecting the resulting mixture to a flotation operation; substantially as described.

4:. The method of efl'ecting the, concentration of minerals by'flotation, which comprises adding to the mineral pulp a small amount ofa thio-urea substance or compound, togetherwith a flotation agent having good frothing qualities, and subjecting the resulting mixture to a flotation operation; substantially as described.

5. The method of effecting the concentration ofminerals by flotation, which comprises adding to the mineral pulp a small amount of an aromatic thio-urea substance or compound, together with a flotation agent having good frothing qualities, and

subjecting the resulting mixture. to a flota-. tion operation; substantially'as described.

6. The method of effecting the'concentration of minerals by flotation, which comprises adding to the mineral pulp a small amount of thiocarbanilid, together with a flotation agent having good frothing qualities, and subjecting the resulting mixture to for; andsubjecting the resulting mixture to a flotation operation; substantially as described.

an organic solvent therefor, andsubjecting" the resulting mixture to a flotation opera-- tion; substantially as described.

10. The method of efl'eoting the concentration of minerals by flotation, which comprises adding to the mineral pulpa small amount of thiocarbanilid together With a small amount of an aromatic amido coma pound, and subjecting the resulting mix- 5 ture to a flotation operation; substantially as described. 4

11. The method of effecting the concentration of copper sulfid oresby flotation, 20 which comprises adding to the ore pulp a 7 small amount of thiocarbanilid, together with a small amount of an alkali and of a flotation agent having good frothing qualities,,and subjecting the resulting mixture to a flotation operation; substantially as described. I g a In testimony whereof, wehereunto aflixv our signatures. Y

i OLEMEND. L. PEEK-INS.

' RALPH E. SAYRE, 

